1. Field of the Invention
The present invention relates to a substrate receiving apparatus and method thereof that prevents substrate damage from occurring when a substrate is loaded/unloaded on/from a cassette.
2. Discussion of the Related Art
Generally, liquid crystal displays (LCDs) having characteristics of power-saving driving, full color realization, high image quality, and the like are widely used as screens in various devices such as watches, calculators, notebook computers and personal computers.
A process of fabricating such a liquid crystal display device mainly includes a substrate preparing process for constituting a liquid crystal display panel and a module assembly process.
In the related art, while the above-mentioned processes are carried out, a specially constituted substrate receiving apparatus is used for transferring a plurality of substrates and panels.
A substrate receiving apparatus for a liquid crystal display device according to a related art is explained by referring to the attached drawings as follows.
FIG. 1A illustrates a layout of a substrate receiving apparatus and a conveying robot according to a related art.
FIG. 1B illustrates a cross-sectional view of a substrate receiving apparatus according to a related art.
FIG. 1C illustrates a layout of a cassette-fixing clamp unit according to a related art.
Referring to FIG. 1A and FIG. 1B, a substrate receiving apparatus according to a related art includes a cassette 102 that receives a plurality of substrates 104, a stage 103 supporting the cassette 102, and at least one port 100 under the stage 103. In this case, the cassette 102 is able to receive about 20 substrates.
A conveying robot 101 selects one of various ports 100, approaches the cassette 102 on the selected port 100, and then loads/unloads the substrates 104 one by one for processing the substrate 104.
Referring to FIG. 1C, a fixing clamp 105 is used for fixing the cassette 102 mounted on the stage 103 (shown in FIG. 1B). A cylinder 106 is installed on the clamp 105 so as to move the clamp forward/backward in a direction of the arrow. A side roller 107 is installed on the clamp 105 so as to reduce friction with the cassette 102.
Once the cassette is fixed thereto by the clamp 105, the conveying robot 101 carries out the function of taking the substrates 104 out one by one to process the substrates 104.
FIG. 2A and FIG. 2B illustrate receiving statuses of the substrates 104 put in the cassette 102 according to a related art.
Referring to FIG. 2A, plates 202 are placed at both inner sides of a cassette 102 so as to support a substrate 104. The substrate 104 is placed on the plates 202. In this case, the plates 202 leave a predetermined interval from each other so that a robot arm 201 may enter a space between the substrates 104. Yet, a central portion of each of the substrates 104 droops downward due to its own weight.
Referring to FIG. 2B, an extent of the drooping increases as the substrate 104 is made to be thinner. Once the substrate 104 droops downward, the robot arm 201 advancing into the cassette for loading/unloading the substrate 104 fails to avoid touching another substrate. Hence, there is a chance the substrates may be damaged or for failure of the substrate.
In order to overcome such a problem there is a method for increasing an interval 206 between the upper and lower plates 202 or a length 207 of each of the plates 202. However, it is very expensive to modify all the cassettes used in a product line. Besides, it is troublesome to use a different cassette according to a thickness of the corresponding substrate 104.